Abstract: A system reduces non-linear distortions in an output signal of an amplifier stage that is configured according to the feed forward principle. An amplifier stage input signal arrives at a main branch of an amplifier. The output signal of the amplifier, which is distorted in a non-linear manner, arrives at an adder. An output of the adder forms the amplifier stage output signal. The output signal which is distorted in a non-linear manner and the amplifier stage input signal are fed to a secondary branch that comprises an error signal device. The error signal device generates an error signal from the delayed amplifier stage input signal and the output signal of the amplifier, which is distorted in a non-linear manner. The error signal is fed to the adder in order to reduce distortions in the amplifier stage output signal. The error signal device comprises at least one transmission device that is provided with a negative group delay time.

Abstract: A digital-analog converter for mobile radiotelephone base stations includes a D flip-flop and a modulator. The D flip-flop is clocked by a clock signal and a digital input signal is fed to an input of the D flip-flop to produce an output signal. The modulator multiplies the output signal produced from the D flip-flop with the clock signal and outputs an analog output signal indicative thereof.

Abstract: A frequency synthesizer, especially for mobile radio base stations, transforms a digital input signal having a first frequency rapidly into a digital output signal having a second frequency. Similar to an N-fractional synthesizer, in the frequency synthesizer, the digital input signal is fed to a series connection having a phase detector, a filter and a voltage-controlled oscillator. The conventional N/N+1 divider provided in the feedback path, as in an N-fractional synthesizer, is replaced by some sort of digital synthesizer that is clocked or supplied with the digital output signal that is produced by the voltage-controlled oscillator.

Abstract: A method for finding the position of a subscriber in a radio communications system combines transmission signals from subscribers to form a transmission sum signal, which is passed by cables from a base station to at least two antenna devices for transmission. Received signals from subscribers are received via the antenna devices and are combined to form a received sum signal, which is passed by cables to the base station. Each individual antenna device is associated with an individual area for the radio supply for the subscribers there. Cables lengths, which are used for signal transmission, for each antenna device are chosen individually such that a round trip delay time measurement which is based on the transmission signal and received signal of a sought subscriber is used to determine an antenna device via which the received signal sought subscriber is received. The position of the sought subscriber is determined via the area which is supplied by radio and is associated with the determined antenna device.

Abstract: An arrangement for runtime compensation of a runtime difference, arising through emulation of a high frequency signal, is disclosed, with a signal x(t), for emulation by a signal processing device, which emulates the signal x(t) with a signal x(t) and a device for determining a difference signal between the signals x(t) and x(t). The arrangement is characterized in that the emulated signal x(t) is conducted via filter with a negative group runtime for certain frequency ranges.

Abstract: A digital-analog converter for mobile radiotelephone base stations includes a D flip-flop and a modulator. The D flip-flop is clocked by a clock signal and a digital input signal is fed to an input of the D flip-flop to produce an output signal. The modulator multiplies the output signal produced from the D flip-flop with the clock signal and outputs an analog output signal indicative thereof.

Abstract: The invention relates to a frequency synthesizer, especially for mobile radio base stations, which transforms a digital input signal having a first frequency rapidly into a digital output signal having a second frequency. Similar to an N-fractional synthesizer, in the inventive frequency synthesizer the digital input signal is fed to a series connection consisting of a phase detector, a filter and a voltage-controlled oscillator. An essential feature of the invention is that the conventional N/N+1 divider provided in the feedback path, as in an N-fractional synthesizer, is replaced by some sort of digital synthesizer that is clocked or supplied with the digital output signal that is produced by the voltage-controlled oscillator.

Abstract: On an acousto-optical add/drop multiplexer to whose input the wavelength-division multiplex signal is applied, a plurality of surface acoustic waves are excited at specific frequencies and in each case a portion of the light power is separated from wavelength-division multiplex channels at an optical frequency which is governed by the frequency of such a surface acoustic wave; a superheterodyne receiver (HE), to whose input side the separated light power elements with one polarization are applied as well as light power elements with another polarization which are output from the non-separated elements of the wavelength-division multiplex signal emits an output signal which corresponds to the light power levels which are transmitted in a channel-specific manner in the individual wavelength-division multiplex channels, with whose aid a regulating device in each case separately readjusts the light power transmitted in the individual wavelength-division multiplex channels to a predetermined value.

Abstract: A form of modulation that is variable in terms of its number of steps is provided in a mobile communication system using a digital modulation of a modulation carrier. The number of steps of the modulation in the respective digital transmission channel is thereby adaptively matched to the respectively existing transmission conditions during operation such that a largely constant error probability is achieved in this transmission channel. The modulation method is to be preferably applied in a mobile communication system with combined time-division multiplex/frequency-division multiplex multiple access methods (TDMA/FDMA).

Abstract: The resonant circuit has at least one resonant body of a semiconductor material anchored on the surface of a semiconductor substrate, at least one first electrode being arranged at said semiconductor material, and at least one second electrode. The first and second electrode are arranged lying opposite one another. When an AC-superimposed DC voltage is applied between the first and the second electrode, the resonant body is excited to mechanical oscillation by the DC voltage. In particular, the resonant circuit can be monoically integrated in electronic circuits.

Abstract: A method for fabricating a silicon semiconductor substrate having an optical fiber coupled to an integrated waveguide by anisotropically etching a V-shaped groove aligned with the integrated waveguide into the substrate. The integrated waveguide is provided with a freely accessible end surface situated opposite the end of the V-shaped groove. The freely accessible end surface is formed by first producing a recess in the silicon semiconductor substrate. The recess is made by anisotropically etching a piece of the substrate from the surface opposite the surface bearing said V-shaped groove. The piece is bared down to a region surrounding said integrated waveguide but the piece remains connected to the waveguide by a V-shaped notch. Then pressure is exerted on the piece, causing it to break off at the V-shaped notch, thus forming the freely accessible end surface of the waveguide as a fracture surface. An optical fiber is inserted into the V-shaped groove and extended up to the freely accessible end surface.

Abstract: In a semiconductor element is shown having a silicon layer, a waveguide comprising silicon and a diode structure connected with external, conductive contacts. The diode structure is provided in such an arrangement to the waveguide that the diode structure can be influenced by electron hole pairs generated by photons in the waveguide. In order to create a semiconductor element with an optical waveguide and an integrated diode structure, in which high losses in the optical waveguide are avoided, the waveguide is weakly doped, and a germanium-rich layer is a component of the diode structure. The semiconductor element is well suited as a component in integrated optics for optical-electrical conversion.